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Help scientists untangle the complex relationships between caterpillars, the plants they eat, the parasitoids that eat them, and the changes in climate that will reshape the rain forest.

On this Earthwatch Expedition, you’ll search the forests of Costa Rica for caterpillars and take specimens to the lab for state-of-the-art chemical analysis and observation. Prepare to be dazzled by the array of shapes and colors that caterpillars come in, most of which serve as natural defenses against their predators. You may even find a new species—it’s happened before.

Project scientists have data on over 9,500 species of both caterpillars and the wasps and flies, called parasitoids, that kill the caterpillars by laying eggs in them (this gives their offspring a safe, food-rich place to grow). Caterpillars and parasitoids live in a delicate balance, one that climate change could destroy. For one thing, this research has shown that warmer temperatures speed up caterpillar growth. This means that parasitoids can’t use them as hosts because their life cycles are out of synch, and the parasitoids die off. With fewer parasitoids to keep them in check, caterpillars breed like crazy and decimate their food plants.

Loss of biodiversity—the variety of living things on Earth—is the ultimate price of such imbalances. On this expedition, you will help preserve the complex, wondrous variety of plant and animal life while working with some surprisingly fascinating creatures.

Duration

Lead scientists

Accommodations and food

Why the research is important

Why the research is important

Some caterpillars can eat up to 27,000 times their body weight in just few weeks. If they become too plentiful, they can wipe out their host plants.

The warmer temperatures and stronger storms expected from climate change could make it impossible for parasitoids to keep caterpillars in check.

To protect the natural world, we need as much information as possible about its organisms and how they interact—and that’s what these scientists are doing with caterpillars and parasitoids.

With the help of Earthwatchers in Costa Rica (and four other sites), they have scoured the forest for thousands of specimens and have logged a wealth of data on how different species relate to one another. This information is a huge benefit to both local communities and other scientists. Say a farmer wants to stop a crop-eating pest like the armyworm (a caterpillar) without chemicals. With data volunteers have helped collect, it’s possible to predict which parasitoids could naturally control which caterpillars.

You may find a new species of caterpillar!

But preserving biodiversity is perhaps the most important result. Nature provides crucial services for humans—food, water, income, temperature regulation—that climate change will certainly reshape. The loss of species costs us money, health, and happiness, and diminishes the richness of the world around us.

Help these scientists find out what could be coming by testing what happens when the balance between species is thrown off. In one experiment, scientists and volunteers removed caterpillars completely from a few forest patches. Fifteen months later, those areas had 40% fewer plant species than the surrounding forest. Plants that would have otherwise been controlled by their predators—caterpillars—drove others out of existence.

About the research area

With its huge range of plants, birds, and other animals, Costa Rica is one of the most biodiverse countries on Earth. It boasts 25 national parks, all of which offer stunning wildlife viewing. During a typical walk, you might spot peccaries, coatis, monkeys, and an array of tropical birds. The lucky visitor might even see an ocelot, jaguar, or other cat skulking through the forest. The caterpillars you’ll work with on this project make up only a fraction of the estimated 8,000 species around La Selva alone (about 7,500 moth species and 500 butterfly species).

La Selva and Tirimbina are located in the Caribbean lowlands of Costa Rica near the town of Puerto Viejo de Sarapiquí in Heredia Province. The area is at the confluence of two rivers, Rio Sarapiquí and Rio Puerto Viejo. Although Tirimbina is only 840 acres (340 hectares) in area, it has gained recognition as a Costa Rican National Wildlife Refuge. In addition to tropical forest, it has abandoned pasture and cacao plantations to explore.

Get to know the Costa Rican tropical forest—and some of its tiniest inhabitants—very well. You'll help researchers:

Hike to collect caterpillars. You’ll spend most of your time in the field gathering caterpillars and food plants, which will give you lots of opportunities to hike on and off trail. Field staff will give you plenty of tips on how to find these small creatures. You’ll also hike to previously located sites where food plants grow to gather leaves to feed the caterpillars being reared in the lab.

Examine caterpillars in the lab. Back at the research stations, you’ll help sort through the caterpillars collected in the field, checking them for parasitoids and either releasing them or putting them in the caterpillar “zoo” for further study. You’ll also help conduct fascinating experiments and chemical analyses.

When you're not working with caterpillars, you'll have at least a day and a half of recreational time; field staff will help you find exciting touring options, or you can choose to relax at the field station. During most late afternoons you can to relax, socialize, and enjoy the forest sights. Days will end with dinner and talks or preparation for the following day of fieldwork.

MEET THE LEAD SCIENTIST

ABOUT Lee Dyer

Accommodations and Food

Accommodations and Food

TO BE DETERMINED

You’ll split your time between La Selva Biological Station and the more rustic Tirimbina Rain forest Center, deep in the forest. Keep an eye out for monkeys, sloths, toucans, and, of course, butterflies. You’ll share rooms with bunk beds at both places, and La Selva offers Internet access and laundry. At Tirimbina, you can enjoy a friendly game on the futbol field or a dip in the nearby swimming hole.

Talented cooks will prepare traditional Latin American fare - lots of rice, beans, and fresh fruit - at La Selva. At Tirimbina, you’ll help prepare meals alongside other international visitors. For days in the field, you’ll take bagged lunches of sandwiches, fruit, juice, and cookies.